The invention is related to providing a lubricating apparatus, and particularly to providing an oil pickup structure for a compressor for smoothly supplying lubricant to the connecting portion.
A conventional oil pickup structure includes an apparatus connected slantly to the rotating shaft of the compressor so as to supply the lubricant to the supporting area of the rotating shaft by the centrifugal force during operation. That is, a conventional apparatus could not avoid the deterioration of its performance in a compressor due to the refrigerating gas discharged during the supply of the lubricant since the refrigerating gas is inherently contained in the lubricating oil.
In light of this point, an oil pickup structure has been developed in a way that, as shown in FIG. 1, small hole 24 is formed on the upper of tube 17. But, it is difficult to discharge the refrigerating gas introduced with the lubricant through the hole. Due to it, a roaring noise is generated. Further, if the shape of the tube has been made in the lower bending configuration whose rotating radius is large, the pumping force is decreased since a large amount of bubbles is generated, thereby delaying the pumping time. Herein the lubricant is dispersed by the vane portion 31 which is arranged in the lower portion of the tube 17, represents a the roaring noise.
FIG. 2 represents a configuration similar to that of FIG. 1. Herein an oil pickup structure decreases the noise caused by the supporting portion of the rotating shaft since the refrigerating gas is moved upward through the tube 18 and discharged through the chip hole 62, but the pumping time of the lubricant is prolonged due to the flowing resistance generated by curving the lubricant passage 61 by 90 degree.
In order to resolve these problems, a lubricating device of FIG. 3 has been developed and disclosed in detail in U.S. Pat. No. 3,858,658 incorporated herein by reference. This apparatus, used in a compressor of a vertical axis 4 for a refrigerator, includes a upper part with a circular section and FIG. 3B and A lower part whose end section has a spiral shape FIG. 3C linked with a circular section of the upper part of the tube 16, FIG. 4 by means of rectilinear generatrices. The tube 16 also has a longitudinal fissure 15 and a paddle 32 fixed to its central parts. The tube 16 is placed in a slanting position at the end of the crankshaft of the compressor and rotates therewith to pump oil from the sump to the parts feeding lubrication while separating particles of refrigerating gas from the oil at the same time. Therefore, a large amount of the gas as well as the oil is intaken through the fissure of the lower part having a relatively larger area than that of the upper into the tube. It has the defect that abnormal noise is generated between the crank shaft ad the bearing, since the intaken gas can not be smoothly discharged through the fissure of the upper part narrower than that of the lower part out of the tube 16.
On the contrary, if the lower part of the tube 16 is being narrowed and the upper portion is widen, it has an advantage that the intaken gas can be smoothly discharged through the fissure of the upper part, but it has disadvantages that a little amount of the oil is intaken through a relatively smaller fissure of the lower part and the pumping force is reduced due to a relatively larger fissure 15 of the upper part. Also, a paddle 32 is rotated while inserted into the lubricant. It generates bubbles reducing the possibility of the oil transmitting noise through the tube to the compressor. But, a paddle 32 immersed in the refrigerating oil functions to scatter the oil, with the result that noise is generated due to the falling of drops of the oil.